I want to do a compression check on my Mercruiser 525. How do I disable the fuel and ignition while cranking over the motor for each cylinder compression check?

if you pull the kill switch it should still turn over with no fuel or spark....at least my boat does lol

Stewart

Thanks. Will try.

yes, this would provide you an overiweve about the compression!

make sure your kill switch works - 2 ways to test it is pull it while engine running and then return ignition key to off - then try to restart engine and listen for the fuel pump to come on making sure about that one. . Put kill switch back on and restart your start your engine.

you can always pull the fuses as well